Fault-Tolerant Control Strategy Based on Speed Ripple Compensator for Five-Phase PMSM Under Coil Inter-Turn Short Circuit Fault Condition

Five-phase permanent magnet synchronous motor (PMSM) is wildly used in the applications with high reliability requirement because of the ability of fault tolerance. Single-phase coil inter-turn short circuit (ITSC) fault is one of the most common faults of PMSM. When PMSM keeps operating under coil ITSC fault condition, the interaction between short circuit current and magnetic field of rotor permanent magnet will generate fault electromagnetic torque, which will cause speed ripple. In this paper, the generation of the fault electromagnetic torque of five-phase PMSM with single-phase coil ITSC fault is theoretically analyzed, and a single-phase coil ITSC fault-tolerant control strategy based on speed ripple compensator (SRC) is proposed. The SRC, which has the advantages of simple structure and less computational burden, can suppress pulsating components of different frequency in the speed ripple caused by the fault electromagnetic torque at the same time without changing the control parameters. The simulation results show that the torque ripple and speed ripple can be reduced significantly by the SRC.